There’s nothing more frustrating than seeing the excitement on your kid’s face vanish when their RZR 170 sputters and dies. It starts up, teases you with a moment of hope, and then… silence. You’re left with a stalled machine and a disappointed young rider.
We’ve all been there. That moment of “what now?” can be a real headache. You know the engine wants to go, but something is holding it back.
Promise yourself this: you can tackle this. This comprehensive guide is your new best friend. We’re going to walk you through a systematic, step-by-step process to figure out exactly why your polaris rzr 170 wont stay running. We’ll start with the simple stuff and work our way up, giving you the confidence to get your hands dirty and get that mini-RZR ripping again.
Start with the Basics: The Easiest Fixes First
Before you start tearing into the engine, let’s check the simple things. More often than not, the solution is easier than you think. Don’t skip these steps—they could save you hours of work.
Step 1: Check the Parking Brake Safety Switch
This is one of the most common problems with a Polaris RZR 170 that won’t stay running. Polaris designed a safety feature that kills the engine if the parking brake isn’t fully engaged when starting. Sometimes, this switch gets sticky or goes bad.
Jiggle the parking brake lever. Make sure it’s fully, firmly engaged. Try starting it again. If it stays running, you’ve found your culprit. You may need to adjust or replace the parking brake sensor if this is a recurring issue.
Step 2: Is the Choke On or Off?
The RZR 170 has a manual choke. When the engine is cold, you need the choke on (lever up) to start it. But once it warms up for 30-60 seconds, you must turn the choke off (lever down).
If you leave the choke on, the engine will run too rich, foul the spark plug, and die. If your RZR starts and then dies a minute later, this is a very likely cause. Make sure you’re operating the choke correctly.
Step 3: Evaluate Your Fuel
Old gas is bad gas. Gasoline, especially ethanol-blended fuel, can go bad in as little as 30 days. It loses its combustibility and can clog up your fuel system with varnish and gunk.
If the RZR has been sitting for a month or more, the fuel is your prime suspect. The best practice is to drain the old fuel from the tank and carburetor bowl and replace it with fresh, non-ethanol premium gasoline if you can find it. This is a simple, eco-friendly step that solves countless running issues.
Diving Deeper: Your Polaris RZR 170 Wont Stay Running Fuel System Checklist
If the basics didn’t solve it, it’s time to investigate the fuel delivery system. For an engine to run, it needs a consistent supply of clean fuel. This section of our guide will show you how to ensure that’s happening.
The Fuel Petcock and Filter
The RZR 170 has a fuel petcock on the tank that acts as an on/off/reserve valve. Make sure it’s turned to the “ON” position. These can sometimes get clogged with debris from the tank.
Follow the fuel line from the petcock and you’ll find a small, inline fuel filter. These filters are cheap and get clogged easily. If it looks dark or full of sediment, replace it. It’s one of the most effective and affordable troubleshooting steps you can take.
- Turn the petcock to “OFF”.
- Use pliers to slide the clamps off the fuel lines connected to the filter.
- Pull the old filter out and install the new one, making sure the arrow points toward the carburetor.
- Re-secure the clamps and turn the petcock back to “ON”.
Inspecting the Carburetor
The carburetor is where fuel and air mix. If your polaris rzr 170 wont stay running, a dirty carburetor is a very common problem, especially if old fuel was left in it. The tiny passages inside, called jets, get clogged easily.
The most likely culprit inside the carb is the pilot jet. This jet controls the fuel mixture at idle. If it’s clogged, the engine will start with the choke (which provides an alternate fuel circuit) but will die as soon as the choke is turned off.
Cleaning a carburetor can be a DIY job if you’re patient. You’ll need a can of carb cleaner and some small tools. You must remove the pilot and main jets and ensure you can see daylight through them. If you’re not comfortable taking the carb apart, a local powersports shop can do this for you.
Is Your Engine Gasping for Air? Checking the Intake System
An engine needs three things to run: fuel, spark, and air. We’ve covered fuel, so now let’s look at the air supply. A restricted intake can choke an engine out, causing it to stall.
Clean or Replace the Air Filter
This is maintenance 101. The air filter is your engine’s only line of defense against dirt, dust, and sand. A filthy, clogged air filter will starve the engine of oxygen, causing it to run rich, bog down, and stall.
Pull the air filter out and inspect it. If it’s caked in dirt, it’s time for a cleaning or replacement. A clean air filter is one of the best practices for a healthy engine and is a critical part of any polaris rzr 170 wont stay running care guide.
Check for Air Leaks
After the carburetor, the air/fuel mixture travels through a rubber “intake boot” to the engine. Over time, this rubber can crack or the clamps can come loose, creating a vacuum leak.
A vacuum leak sucks in extra, unmetered air, which leans out the fuel mixture and can cause stalling and an erratic idle. With the engine running (if you can keep it going for a few seconds), carefully spray a little carb cleaner around the intake boot. If the engine RPM changes, you’ve found a leak that needs to be sealed.
The Spark of Life: Troubleshooting the Ignition System
If you’re confident the RZR is getting the right amount of fuel and air, the next piece of the puzzle is spark. A weak or inconsistent spark won’t be able to ignite the fuel mixture properly, leading to stalling.
Inspect and Replace the Spark Plug
A spark plug is a small part that does a huge job. They are also wear items and don’t last forever. Pull the spark plug out using a spark plug socket.
Look at the tip. Is it black and sooty (running rich)? White and blistered (running lean/hot)? Or covered in oil? A healthy plug should be a light tan or grayish color. If it looks bad, or if you don’t know how old it is, just replace it. They are inexpensive and a fundamental part of troubleshooting.
Check for Strong Spark
With the new spark plug, you should test for spark. You can buy a cheap inline spark tester from any auto parts store. This is the safest way to do it.
It plugs in between your spark plug and the plug wire. When you crank the engine, a light inside the tester will flash. You’re looking for a bright, consistent blueish-white flash. If the light is weak, orange, or intermittent, you may have a problem with the ignition coil or CDI box.
Advanced Diagnostics: When Simple Fixes Aren’t Enough
If you’ve gone through all the steps above and your RZR 170 still won’t stay running, the issue might be more internal. These steps require a bit more mechanical skill and special tools.
Checking Valve Clearance
The engine’s intake and exhaust valves control the flow of air/fuel in and exhaust out. They need a very specific, tiny gap (clearance) to operate correctly. If this gap is too tight, the valves won’t close fully, causing a loss of compression and making the engine impossible to keep running at idle.
Checking and adjusting valves requires a feeler gauge and removing the valve cover. This is a more involved job, but it’s a common issue on these small engines. If you’re not confident, this is a good time to consult your service manual or a professional mechanic.
Performing a Compression Test
Engine compression is a measure of how well the cylinder seals. Low compression means the engine can’t effectively squeeze the air/fuel mixture, leading to a loss of power and stalling.
You’ll need a compression tester that screws into the spark plug hole. A healthy RZR 170 engine should have compression in the 150-170 PSI range. If your reading is significantly lower, it points to internal engine problems like worn piston rings or a bad valve seal.
Frequently Asked Questions About Polaris RZR 170 Wont Stay Running
Why does my RZR 170 only run with the choke on?
This is a classic symptom of a clogged pilot jet in the carburetor. The choke provides a separate enrichment circuit that bypasses the clogged idle circuit. When you turn the choke off, the engine is starved of fuel at idle and dies. The carburetor needs a thorough cleaning.
Can a bad battery cause the RZR 170 to stall?
While a weak battery can cause starting issues, it’s less likely to be the cause of stalling once the engine is running. The machine’s stator and charging system should power the ignition system while it’s running. However, a severely faulty battery could potentially cause electrical issues, so it’s always good to ensure it’s fully charged and healthy.
How often should I clean the carburetor on my RZR 170?
There’s no set schedule. The need for cleaning is dictated by your fuel quality and how often the machine sits. The best way to prevent clogs is to use high-quality, non-ethanol fuel whenever possible and to add a fuel stabilizer if you know the RZR will be sitting for more than a few weeks. If you do this, you may never need to clean the carb.
Working through a machine that won’t cooperate is a right of passage for any off-roader. By following these steps logically, you’re not just guessing—you’re diagnosing. You’re learning how your RZR 170 works and gaining the skills to keep it running for years of fun.
Take your time, be safe, and don’t be afraid to double-check your work. You’ll solve this problem and get that smile back on your young rider’s face. Now grab your tools and get to it!
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